Chronic inflammation resulting from infection of the gingiva (gum tissue) leads to a separation of these tissues from the root surfaces of the teeth, forming spaces known as "periodontal pockets". The periodontal pockets become more and more infected so that, if not treated, teeth are eventually lost because of the extensive destruction of the supporting tissue of the teeth.
In order to stop this destructive process and prevent loss of teeth, the periodontal pockets and the infected tissue therein must be eliminated. Formerly this required a surgical procedure known as a "gingivectomy" in which the entire infected gum margin is cut away. In recent years, the technique has been modified owing to the inaesthetic appearance and tooth sensitivies most often resultant with such an approach. Currently, the periodontal pockets are surgically opened so as to provide access to the infected tissues therein. These tissues are surgically removed and the gum margins are closed again so as to contact the tooth surfaces in such a manner that, after guided healing, no periodontal pocket nor associated infection remain.
Prior art periodontal surgery suffers from a number of drawbacks. There is frequently significant bleeding which impedes the surgeon's vision. The operation requires the provision of a local anaesthetic for pain control, resulting in post-operative pain and swelling to the patient. Additionally, an antibiotic cover must generally be provided.
In order to overcome some of these these drawbacks, surgical lasers have been employed in an attempt to provide dry, bloodless surgery which produces minimal post-operative discomfort to the patient. The use of lasers can obviate the need for a local anaesthetic and provides a sterilised field requiring no antibiotic cover. Such an approach is described, for example, in an article entitled "The Laser Gingivectomy" by Robert M. Pick et al appearing in The Journal of Periodontology, August, 1985 Vol. 56 Number 8. Pick et al employ a CO.sub.2 laser with some success to avoid some of the problems described above relating to the surgical gingivectomy.
The CO.sub.2 laser used by Pick et al is a surgical laser as opposed to high power industrial lasers and so-called "soft medical lasers". The latter are relatively low power lasers which are employed in laser therapy applications, as opposed to surgical lasers which are intended for cutting through tissue and for destroying diseased tissue by vaporisation thereof.
However, the approach used by Pick et al suffers from a number of drawbacks, due in part to the limitations of the laser apparatus employed. Thus, no protective shielding is provided for the laser and, therefore, extreme caution must be taken during its use. Furthermore, the laser employed by Pick et al is not adapted physically to touch the infected tissue and therefore provides no tactile feedback to the surgeon. This contrasts with standard surgical procedures using scalpels and renders the laser apparatus described by Pick et al relatively difficult to use.
The use of lasers per se in dentistry is described in a paper entitled "Basic Researches and Clinical Applications in Oral Surgery of Nd-YAG Laser with Handpieces Designed for Dentistry" by Takumi Sato et al, and appearing in The Journal of Japan Society for Laser Medicine, Vol. 5, No. 3: 405-408, 1985.
Sato et al describe a Nd-YAG laser apparatus specially adapted for dental use and suitable for the laser gingivectomy, similar to that performed by Pick et al with the CO.sub.2 laser. The handpiece in the Nd-YAG laser is terminated in a sapphire tip coincident with a focussed laser beam, so that the laser cuts through tissue at its point of contact therewith. However, the apparatus described by Sato et al is suitable for external use only as are hitherto proposed CO.sub.2 laser handpieces. Neither is able to perform the more extensive procedures associated with periodontal surgery, demanding opening the periodontal pocket, as outlined above.